Liquefaction and gas boosting system



y 1950 o. E. GAMMILL, JR 2,508,821

LIQUEFACTION AND GAS BOOSTING SYSTEM Filed May 50, 1944 IIIICWWDEMSIBLE 6W8 P0176! ll/Vl'.

- 34 6'45 CONOl/lf $095 CONDU/ 7' 6345' H/RGE UN! INVENTOR.

26 BY W ATTORNEY.

Patented May 23, 1950 UNITED STATES PATENT OFFICE LIQUEFAC'I ION AND GAS BOOSTING STEM Oscar E.. Gammill, Jr., Dallas, Tex., assignor to Carrier Corporation, Syracuse, N. Y., a corporation of Delaware Application May 30, 1944, Serial No. 538,099 Claims. (Cl.62-175.5)

The general object. of the invention is to recover, on an efficient basis, desired constituents from a gas stream and then to boost the residual constituents to a, desired degree, the boosted constituents then being returned to a gas well or utilized as desired.-

A feature of the invention resides in the subjection of a stream of gas to a series of stages of refrigeration to the end that recovery of desired constituents is effected at each of the stages.

Another feature of the invention covers the use of a plurality of interchangers served by a plurality of refrigeration systems. The interchangers subject a stream of gas to progressively lower temperatures and simultaneously subject a return stream of gas to progressively higher temperatures. The first stream serves to provide recovered constituents as a result of condensation at progressively lowered temperature levels.

The return stream serves a two-fold purpose:

(1) to effect condensation of compressed gases in the different stages of compression of said refrigeration systems; and (2) to effect more efficient interchange in the constituent recovery steps aforesaid.

Other features and advantages of the applicants recovery and booster system will be more apparent from the following written description of one form of the invention to be read in connection with the accompanying drawing showing a. diagrammaticarrangement illustrative of the intended application Without regard to specific design or structure of the various parts.

Considering the drawing, numerall designates in fragmentary diagrammatic form, a gas well. While the invention is being described in connection with gas drawn from a well, it also applies to, a stream of gas, hydrocarbon constituents, or other combination of gaseous compounds drawn from any desired source. The stream of gas flows from well I through pipe line 2 to a series of interchangers 3, 4 and 5. It will be understood that depending upon the application of the invention, any required number of interchangers of desired capacity and arrangement may be employed. Such interchangers contain a first series of interchanger coils 5, I and 8. While such coils may in practice, at least as to one or more of them, be served by well water, brine from any desired source, cooling medium from a spray pond or cooling tower, or the like, the interchangers illustrated are in this instance served by a plurality of refrigeration systems. In essence, coils 6, 1, and 8 consti-- tute evaporator elements forming part of the rethe condensate forwarded to pump 25.

2 spective refrigeration cycles in which they are located.

Thus, refrigerant compressor 9, preferably a centrifugal compressor driven by a steam turbine, discharges refrigerant at a desired pressure to condenser II), the refrigerant then proceedin through interchanger I l, evaporator coil 6 and back in gaseous state to the compressor. Similarly, stage 2 of refrigeration includes compressor I2, condenser l3, interchanger I4,

and evaporator coil 1. Stage 3 of refrigeration similarly includes compressor [5, condenser l8,

interchanger l1, and evaporator B. The various stages of refrigeration are designed so that the suction temperature in coils 6 corresponding to the suction pressure will be higher than that in coil 1. which in turn will be higher than that in coil 8. The compressors are designed to handle refrigerants, as desired, and are equipped with driving elements capable of providing desired temperatures in the respective evaporators 6 1 and 8. I

The stream of gas from pipe line 2 will first enter interchanger 3 and partial recovery due to the action of evaporator coil 6 upon the gas stream will result in condensed or recovered constituents being precipitated and removed from the interchanger through recovery line l8. The remaining constituentsproceed from interchanger 3 through line [9 to interchanger 4 where the temperature of the evaporator, as pointed out, is lower. As a result further recovery of constituents is accomplished and the condensate is similarly withdrawn through line 20. The process is repeated in interchanger 5 with Undesirable non-condensible gases are removed through purge line 24 as illustrated.

When the remaining constituents leave interchanger 5 they are at a comparatively low temperature, in many instances at minus F. or lower. This will vary depending upon the nature of the gases handled. In any event, the temperature is so low that the remaining constituents leaving interchanger 5 contain at least some matter in liquid state. Fluid pump 25 can, accordingly, effectively boost the remaining constituents to a desirable higher pressure. The result is that the gases will be boosted to a de- 'sirable higher pressure for reinjection into the gas well, as may be necessary. Thus, if gas from well'l flows at a pressure of 2500 pounds per square inch, it is necessary. that the reinjected gas be discharged into the ground at a higher pressure applied by pump 28 to the liquid prevents substantial volatilization thereof during its passage through interchangers H, H and H.

When the remaining constituents leave pump they enter trap 26 and then follow two paths. In a first path, gas from the trap feeds through line 21, coil 28 in interchanger 5, line 29, coil 30 in interchanger 4, line 3|, coil 32 in interchanger 3, and back to the ground through line 88 to maintain pressure therein or, as described above, the gas may be utilized as desired without being .returned to the well. Therefore, it will be seen that the gas in its course from trap 26 is progressively elevated in temperature as it proceeds through interchanger 5, 4 and 3, thus making for greater efficiency in the interchange action throughout the system. The gas being discharged into the round through line 33, is at a moderate difference in temperature from that leaving from the ground through line I.

In the other course, liquid from trap 26 flows through interchangers H, H and ll of the respective stages of refrigeration with the result that progressive sub-cooling of the refrigerant from condensers i8, i3 and i is accomplished, with the flow from interchanger H, in liquid state, proceeding to storage tank 34.

The recovered constituents flowing through lines ll, 20, 2| and 33 are made available by simple liquefaction without recourse to other and more expensive and complicated refining operations. The recovered constituents may then be simply fractionally distilled to obtain the products contained therein such as are contained in natural gasoline.

Since various changes may be made without departing from the spirit of the invention, no limitation is intended with respect to the disclosure in the specification and drawing but only as indicated in the appended claims.

I claim:

1. A system for recovering constituents from gases and boosting residue therefrom in liquefied condition to a higher pressure which comprises a first series of interchangers, a series of refrigeration systems, each refrigeration system including a compressor, a condenser and an evaporator, the evaporators of the refrigeration systems being disposed in said interchangers, a second series of interchangers interposed in the lines connecting the condensers and evaporators of the refrigeration systems, each interchanger of the second series admitting refrigerant from a condenser of said refrigeration systems, a series of return flow heat exchange coils in said first series of interchangers, means for routing gases through said first series of interchangers in one direction, a pump for boosting the pressure of constituents leaving the last interchanger of the first series, a trap for separating gases from the boosted liquid constituents, means for routing the separated gases to the return flow heat exchanger coils in said first series of interchangers in the opposite direction and means for routing boosted constituents in liquefied form through said second series of interchangers in heat exchange relation with refrigerant therein.

2. A method of recovering constituents from gases flowing from a wall which consists in passing the gases from the well in heat exchange relation with a cooling medium to liquefy some portion of said gases, removing the recovered liquefied constituents, passing the remaining gases in heat exchange relation with a second cooling medium at a temperature lower than the temperature of the first cooling medium to recover in liquid form some portion of said gases, removing. the recovered liquefied constituents, passing the remaining gases in heat exchange relation with a third cooling medium at a temperature lower than the temperature of the second cooling medium to liquefy a portion of said gases, boosting the discharge from said third interchanger to a desired higher pressure, separating the liquid from the gases, passing the liquid in heat exchange relation with the cooling mediums in reverse order to sub-cool the mediums, and routing the separated gases in heat exchange relation with the original gases.

3. A method of recovering constituents from gases flowing from a well which consists in passing gases from the well through a plurality of cooling stages in heat exchange relation with a separate cooling medium in each stage to liquefy a portion of the gases in each stage, removing the recovered liquefied constituents from each stage, boosting the fluid from the last stage to a desired higher pressure, separating the liquid from the gases, and passing the separated liquid in heat exchange relation with the cooling mediums in said stages to sub-cool the mediums prior to disposal in heat exchange relation with the gases.

4. A method of recovering constituents according to claim 3 in which the separated gases are routed in heat exchange relation with original gases passing through said cooling stages.

5. A system for recovering constituents from gases and boosting residue therefrom in liquid condition to a higher pressure, which comprises a series of interchangers through which the gas is passed in heat exchange relation with a. cooling medium, means for supplying cooling medium to said series of interchangers, a second series of interchangers, means for passing cooling medium through said second series of interchangers, means for routing gases through said first series of interchangers in one direction, a pump for boosting the pressure of constituents leaving the last interchanger of the first series, a trap for separating gases from the boosted liquid constituents, and means for routing boosted liquid constituents through said second series of interchangers to sub-cool cooling medium supplied to the first series of interchangers.

OSCAR E. GAMMILL, JR.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,101,605 Wright June 30, 1914 1,876,551 Barstow et al Sept. 13, 1932 2,265,558 Ward Dec. 9, 1941 2,297,062 McKee Sept. 29, 1942 2,297,832 Hudson Oct. 6, 1942 2,356,407 Hutchinson Aug. 22, 1944- OTHER REFERENCES Patent No. 2,508,821

Certificate of Correction May 23, 1950 OSCAR E. GAMMILL, JR.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 3, line 70, for the Word well read well;

and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 15th day of August, A. D. 1950.

THOMAS F. MURPHY,

Assistant Oomvm'ssz'oner of Patents. 

